Electrophysiology is a technique that invites consideration of appropriate experiments from the Research Cores. The actions of aquatic toxins are often visible at the neurophysiological level. In the case of the Toxins Core, electrophysiology provides a sophisticated, but quite obvious, bioassay capability. Application of electrophysiological techniques to the Animal Models Core is more diverse in scope, but a unifying principle is that many of our animal models have a neurophysiological component. Electrophysiological applications range from basic studies of how the nervous systems of aquatic animals work to directed investigations on models of disease syndromes. The relevance of a Core to these animal models includes such long-exploited research programs as DNF and relatively new or emerging ones such as the toadfish hyperammonemia model. Additionally, a Core provides a bridge between toxin and Animal Models Research Cores, such as an attempt to study toxin effects on development in zebrafish larvae or the planned studies of toxin effects on hearing in sleeper gobies. Critical to these projects is the expertise of Core Leader Lynne Fieber, who can either execute the experiments or provide training for postdoctoral fellows who plan to dedicate concentrated effort to a particular project. The latter is not trivial as a Core service, because training to the neophyte electrophysiologist stage may take 6 months. But a Core is more than just single cell electrophysiology. A Core also provides Fura 2 apparatus and expertise, which is an interest of several of the investigators (e. g., Gawley via Berry). The proposed research on the toadfish hyperammonemia model will include new neurophysiological experiments requiring expansion of the core to include brain slice technology.